1. Field of the Invention
The present invention relates to blowers for circulating cooling air through machines, and in particular, the present invention relates to blowers which include an anti-reverse flow mechanism.
2. Description of the Related Art
Many electrically-powered machines include a housing in which electrical components such as circuits and motors are contained. During running of the machines, the electrical components within the machines generate heat which must be continuously vented from the machines to cool the internal electrical components. Typically, such machines include one or more internal blowers, each including an electric motor connected to an impeller which is disposed within a blower housing, the blower housing having an inlet in airflow communication with the interior of the machine housing and an outlet in airflow communication with an opening in the machine housing. In operation, rotation of the impeller by the motor draws cooling air from externally of the machine through an inlet in the machine housing, circulates the cooling air across and around the electrical components within the machine to cool the electrical components, and vents the heated exhaust air outwardly of the machine housing through the blower outlets. Many electrical machines include several such blowers to provide increased flow of cooling air, as well as redundancy should one of the blowers fail.
A problem with the foregoing arrangement is that if one of the blowers fails for any reason, the impeller within that blower becomes stationary, yet the outlet of the failed blower remains in airflow communication with the atmosphere externally of the machine. Continued operation of the remaining operable blowers induces a flow of cooling air into the machine through both the air inlet of the machine housing and through the outlet of the failed blower. The foregoing disrupts the normal flow of cooling air through the machine, thereby reducing the effectiveness of the cooling of the internal components of the machine, possibly leading to overheating. Additionally, when a blower fails, disruption of the flow of cooling air places additional operational strain on the remaining operating blowers.
What is needed is an improved blower for use with machines having internal components which require cooling.